This invention relates generally to semiconductor manufacture, and more particularly to an improved semiconductor component having adjustable characteristics and configurations. This invention also relates to a method for fabricating the component, and to systems incorporating the component.
Semiconductor components, such as chip scale packages, ball grid array (BGA) devices, flip chip devices, and bare dice include terminal contacts, such as contact balls, contact bumps or contact pins. The terminal contacts provide the input/output configuration for a component, and permit the component to be surface mounted to a supporting substrate, such as a printed circuit board (PCB). Semiconductor components also include semiconductor dice, and the terminal contacts can be formed on substrates attached to the dice, or in some cases formed directly on the dice. For some components, such as chip scale packages, BGA devices, and bumped dice, the terminal contacts can be arranged in a dense grid array, such as a ball grid array (BGA), or a fine ball grid array (FBGA).
The terminal contacts are in electrical communication with integrated circuits, and other electrical elements, contained on the dice. Typically the components include patterns of conductors that provide separate electrical paths between the terminal contacts and the integrated circuits. The conductors can comprise metal traces formed on substrates attached to the dice, or formed directly on the dice. The physical and electrical characteristics of these conductors can affect the performance of the component, and the integrity of the signals transmitted through the terminal contacts to or from the integrated circuits on the component.
For example, plating buses are routinely used to electrically connect all of the conductors on a component during the fabrication process. The plating buses facilitate plating of bonding pads for the terminal contacts, and wire bonding pads for wire bonding the conductors to the dice. Following the plating process, the plating buses are trimmed, such that the conductors are no longer electrically connected to one another. However, portions of the plating buses can remain on some of the conductors following the trimming process. These remnant portions of the plating buses add mass and length to the conductors, which can affect electrical characteristics, such as inductance, capacitance and resistance. Other physical characteristics such as overall lengths, location on the component and proximity to other elements can also affect the electrical characteristics of the conductors.
The terminal contacts associated with the conductors will also have different electrical characteristics, and the characteristics of the signals transmitted through the terminal contacts will be different. These signal variations can adversely affect the operation of the integrated circuits on the components, particularly at high clocking speeds (e.g., 500 MHz or greater). It would be desirable to have the capability to adjust the electrical characteristics of the conductors and terminal contacts for semiconductor components, and of other elements of the components as well.
It would be also be advantageous to be able to adjust the electrical configuration of the components as well. For example, it may be necessary to electrically connect or disconnect different terminal contacts on a component to alter the input/output configuration of the component. This may be necessary because standardized components are often fabricated with different types of dice. As such, the configuration of the terminal contacts for a component containing a die with a X4 pin assignment configuration may be different than the configuration required for the same component having a die with a X16 pin assignment configuration. In the prior art different input/output configurations have been achieved by using different layouts for the terminal contacts and the conductors, or by using different wire bonding arrangements between the dice and the conductors.
Also in the prior art, fuses have been used for isolating defective circuitry and for substituting redundant circuitry on a component. For example, a 16 megabit DRAM memory die may have a small percentage of cells that fail following burn-in testing. Fuses can be used to isolate defective integrated circuitry, and to substitute redundant integrated circuitry. Fuses can be controlled using electrical signals, or by using a laser beam directed at a portion of the fuse.
Fuses have also been used in the art to lock in operating clock multipliers for microprocessor components. This type of microprocessor is manufactured by Advanced Micro Devices, Inc. of Sunnyvale, Calif., under the trademark xe2x80x9cATHLONxe2x80x9d.
The present invention provides a method for adjusting the characteristics of semiconductor components and elements thereof, and for customizing the input/output and electrical configuration of semiconductor components as well.
In accordance with the present invention, an adjustable semiconductor component, a method for fabricating the component, and electronic assemblies incorporating the component, are provided.
The component includes a substrate, a semiconductor die attached to the substrate, and terminal contacts on the substrate in electrical communication with the die. The component also includes adjustment circuitry on the substrate configured to adjust physical or electrical characteristics of the component or elements thereof.
The adjustment circuitry includes conductors in electrical communication with the integrated circuits on the die and with the terminal contacts. The adjustment circuitry also includes programmable links, such as fuses or anti-fuses, in electrical communication with the conductors. The programmable links are configured for placement into different states (e.g., short or open) using lasers or electronic signals.
Depending on the layout of the conductors and programmable links, different physical or electrical characteristics can be adjusted by the adjustment circuitry. For example, the adjustment circuitry can be configured to trim the conductors, such as to trim portions of plating buses associated with the conductors. In addition, the adjustment circuitry can include capacitors for adding capacitance to the conductors. Further, the adjustment circuitry can include conductive loops for adding inductance to the conductors.
The adjustment circuitry can also be used to change the input/output configuration of the terminal contacts, and thus the electrical configuration of the component. In this regard, standard substrates can be wired to different types of dice using a standardized wire bonding arrangement. The electrical paths to the terminal contacts can then be connected or disconnected using the conductors and the programmable links to achieve a desired input/output configuration. For example, memory dice can be wire bonded to the conductors at the widest configuration possible (e.g., sixteen DQs (X16)). For a die having a sixteen DQs configuration (X16), no changes to the conductors are required. For a die having a four DQs configuration (X4), the programmable links can be configured to remove all of the conductors associated with the unused 12 DQs.
A method for fabricating the adjustable component can be performed on a strip, such as an organic leadframe, containing multiple substrates, which can be singulated into individual components. The method includes the step of forming the adjustment circuitry on the substrates by forming the conductors and the programmable links in a required layout. Depending on layout and elements, the adjustment circuitry can be configured to adjust different physical and electrical characteristics of the conductors, or the input/output configuration of the terminal contacts. The method also includes the step of placing the programmable links in a selected state (e.g., short or open) to connect or disconnect the conductors, and to achieve the desired adjustment. Depending on the type of programmable link, the placing step can be performed using a laser or electronic signals.
The component can be used to construct systems such as MCM packages, multi chip modules and circuit boards.